Large airships were too sensitive to wind gusts and too sluggish to win against aeroplanes. But today, they have a chance to make a spectacular return.
For decades, die-hard fans of airships have had to accept the fact that their beloved airborne vessels had no chance of making their way back to air travel routes. The ever more technologically advanced aeroplanes are more comfortable and practical than these sluggish giants. Yet the situation changed over a year ago when people in Sweden started talking about ‘flight shame’. Along with the heightened fear of global warming, calculations were being made that, for example, a Boeing 747 emits as much carbon dioxide into the air during 24 hours of flight as 250 passenger cars riding uninterruptedly for a year. Although aeroplanes are responsible for only 4% of the CO2 that goes into the atmosphere in the territory of the European Union, ‘flight shame’ became a hit. The Green parties, especially in Germany, started to bang the alarm that in Europe 45% of all flights are operated on routes shorter than 500 kilometres. The first airlines have just embraced this new trend; at the end of 2019, Dutch airline KLM announced that as of March they will replace flight connections from Amsterdam to Brussels with train routes, together with railway operator Thalys. Likewise, Air France – part of the same holding company as KLM – announced a New Year’s resolution that by 2021, the French air carrier will reduce its domestic flights by 15%.
This trend brings with it the unique opportunity for the much more environmentally-friendly passenger airships to make a triumphant comeback. Much like they did 100 years ago, today’s airships move with the help of propeller-type turbines powered by petrol or diesel engines. However, they emit considerably less CO2 than jet engines. On shorter distances, their speed, on average nine times lower than passenger jets, does not make that much of a difference. Especially since an airship can pick up passengers even in the centre of a metropolis.
Working on refining such a solution is the British company Hybrid Air Vehicles (HAV), founded in 2007. For the past decade, its engineers have been fine-tuning the Airlander 10 project. Standing behind the name is a 92-metres-long vehicle that combines the benefits of an aeroplane and helicopter. It can land and take off from practically any location, take 14 tons of cargo or 60 passengers on board, and then fly at a speed of 140 kilometres per hour for up to five days without having to land. In September 2019 in London, HAV representatives signed a contract with the US company Vertex Aerospace LLC, thereby opening up the possibility of supplying Airlander 10 to the US Department of Defense. Soon after that, the management of HAV announced it was launching preparations for the development of a passenger model powered by electric engines. It is indeed this type of drive unit that could ultimately tip the scales and let these huge machines, the development of which was halted by aeroplanes 100 years ago, take to the skies once more.
A balloon with an engine
The balloon designed and built by Joseph and Jacques Montgolfier never became a useful flying machine due to one fundamental drawback: the direction that it flew in was defined by the blowing wind. For several decades since the summer of 1783, when the brothers held a demonstration of their invention for King Louis XVI by sending a lamb, rooster and duck flying in the air, designers were not be able to overcome this challenge. Granted, there were designs of balloons equipped with sails or even propellers, yet the secret to success lay in a proper drive unit.
French designer Henri Jules Giffard was the first to recognize this. He managed to build a steam engine weighing a little over 100 kilograms that could be installed in the balloon’s gondola. He attached his structure to a cigar-shaped balloon 44 metres in length and filled it with hydrogen. Then he loaded 150 kilograms of coke into the gondola and, on 24th September 1852, set out from Paris to Trappes. The flight proceeded in the direction chosen by Giffard, as the French inventor equipped the vehicle with a triangular sail serving the function of a rudder. Yet the flying giant proved to be helpless in the face of slightly stronger gusts of wind. And once again, the problem lay in the drive unit; to be able to squeeze additional power out of a steam engine, it had to be enlarged. That, in turn, meant that the balloon needed to be bigger to be able to lift the heavier load into the sky. But then the vessel would become even less controllable and vulnerable to the wind.
Numerous designers attempted to improve Giffard’s masterpiece. An airship designed by two captains of the French Army, Charles Renard and Arthur Krebs, looked very promising. The propeller that pushed the vehicle forward was powered by an 8.5 horsepower electric engine, eight times more powerful than Giffard’s steam engine. Thanks to the new drive unit, on 9th August 1884, La France was able to fly eight kilometres in 20 minutes, turn back and return to the place it started from, in spite of the wind. However, Krebs and Renard were not able to manage the issues created by lead acid batteries, as they were too heavy, inefficient and required constant recharging.
The flying count
While French inventors were walking in circles, the Germans set off to conquer the heavens. At the end of the 19th century, Germany was producing the most sophisticated combustion engines in the world. The small yet powerful 28 horsepower engines from the Daimler factory caught the attention of Count Ferdinand von Zeppelin. In 1890, with his 50th birthday on his heels, General von Zeppelin decided to end his military career and engage in the construction of flying machines, thereby fulfilling the dreams of his youth. He caught the aeronautics bug in the US during the Civil War, when he flew in a balloon high above the battle fields as the envoy of the King of Württemberg. 25 years later, he started work on the construction of an innovative airship along with engineer Theodor Kobert. They drew inspiration from the ideas of Hungarian engineer David Schwartz, who had patented the design of an aerostat based on a stiff frame covered with a cotton or aluminium shell, which in turn concealed soft balloons filled with hydrogen.
The fulfilment of his dream proved to be a costly venture, and after eight years of struggling, Von Zeppelin founded the Gesellschaft zur Förderung der Luftschiffahrt in Stuttgart in 1898. In July 1900, on the coast of Lake Constance, he was able to present to shareholders and onlookers his enormous flying machine, the Luftschiff Zeppelin (LZ 1). The cigar-shaped creation, which was 128 metres in length, majestically glided across the sky around 300 metres above the waters of the lake thanks to two Daimler engines. Following that success, and thanks to public fundraisers and lotteries, Von Zeppelin managed to collect 250,000 marks to build yet another airship, abbreviated the LZ 2. The count was expecting that the German army would buy it for 1.5 million marks, but the price proved to be prohibitively high. The army was initially not interested in the LZ 3 model either, although it made 45 flights safely, covering an air distance of 4000 kilometres.
A breakthrough did not come until the matter of the high-profile catastrophe of the LZ 4 airship appeared. The count had turned the LZ 4 into a near masterpiece. The 136-metre-long cigar-shaped vehicle was divided into 17 chambers filled with hydrogen, and attached beneath it was a gondola for the pilots and mechanics, as well as a second luxury passenger gondola. Even King Wilhelm II of Württemberg, who had been persuaded to try the airship out in July of 1908, had no complaints about its level of comfort. After the marketing success, Count Zeppelin announced that his vehicle would make a 24-hour flight without landing, hoping to convince the head of the German army that airships were the perfect solution for attacking the deep hinterland of the enemy. However, on 5th August 1908, a storm forced the LZ 4 pilot Hugon Eckener to land near the city of Echterdingen. There, a gust of the storm wind snapped the airship’s tether and threw it to the ground; the hydrogen exploded and the machine burned to ashes.
That loss pushed Count Zeppelin’s company to the brink of bankruptcy. When the news became widespread, the Germans spontaneously organized a fundraiser for the engineer, whom they were proud of. Soon, he received a sum of over six million marks. This capital allowed Zeppelin to found Luftschiffbau Zeppelin GmbH, a company that, in line with its name (Luftschiffbau means ‘airship engineering’), specialized in the construction of airships. Financial aid was also promised by the Minister of War Karl von Einem, who was increasingly more interested in the combat potential of the flying machines.
Civil and bomber
The mass participation of regular Germans in the fundraiser gave Von Zeppelin the idea that his airships could compete with train travel. In November 1909, he surprised the world by founding the Deutsche Luftschiffahrts Aktiengesellschaft (DELAG) passenger airline. DELAG transported the first 20,000 passengers for free, thereby promoting the trend for air travel, and after that he offered tickets for 200 marks. The amount was equivalent to average monthly wages in Germany at the time; nonethless, its flights were becoming more and more popular. On board the 12 DELAG airships, servicing routes connecting the 10 largest cities of the German Empire, you could travel in the company of aristocrats, politicians, millionaires, generals, or even members of the Imperial Family. In 1914, the airline proudly announced that it had transported 34,000 passengers, and that not one of them died during the flights. Users of highly unreliable aeroplanes could only dream of such statistics at the time.
So when World War I broke out, as the late Walter J. Boyne wrote in his book The Influence of Air Power Upon History, “Germany was so convinced of the potential of dirigibles [...] that it allowed the Army and the Navy to develop their own airship fleets [...].” Ferdinand von Zeppelin, now nearing 80 years of age, was at the height of his fame, while his factories were working at full capacity. Right after the airships, commonly referred to as Zeppelins, appeared over the front lines in France and Great Britain, they raised alarm. In September 1914, in an attempt to anticipate any actions of the enemy, the First Lord of the Admiralty Winston Churchill planned a series of attacks of British bombers on airship bases in Cologne and Düsseldorf, and on an airship manufacturing plant in Friedrichshafen. Despite the great dedication of the airmen, the action brought little effect, as only one Zeppelin burned down on the ground when it was hit by a bomb. Yet the expected retaliation attacks did not take place right away. “At a joint meeting September 1914, representatives of the Army and Navy decided that there were as yet too few airships to bomb England, and further, that they were inhibited by Kaiser Wilhelm’s reluctance to bomb the homes of many of his royal relatives,” Boyne explains. It wasn’t until Germany realized enormous losses on the front that the monarch changed his mind.
“The first attack took place on January 19-20, 1915, with two out of three Zeppelins – L 3 and L 4 – successfully reaching England,” Boyne describes. L 3 dropped over a dozen 50-kilogram bombs on Great Yarmouth, while L 4, led by Captain Magnus von Platen-Hallermund, nearly gave the German Emperor a heart attack. Its bombs fell onto Sandringham House, where the cousin of Wilhelm II, the British King George V, happened to be staying at the time. Luckily nothing happened to him, but the public were shocked by the fact that for the first time in 800 years, since the times of William the Conqueror, an enemy from the continent had launched a direct attack on the monarchs of England.
At first, the airships operated over the island with complete impunity. Rifle bullets shot from the ground were not able to pierce the duralumin sheeting of the vessels’ hulls. In addition, Zeppelins flew at higher altitudes than fighter planes and were able to climb up more quickly, in spite of their large dimensions. For the first time ever in history, Lieutenant Reginald Warneford managed to shoot down the L 37 airship, but this was only after he flew above it in a plane and dropped six bombs from the top. Therefore, the Germans used them even more boldly. “All the fears seemed to be realised on the night of October 13-14 , when five Zeppelins slashed across England, dropping almost two hundred bombs and killing seventy-one people and injuring another 128,” Boyne reports.
The blind path of evolution
“Looking up the clear run of New Bridge Street and Farringdon Road I saw high in the sky a concentrated blaze of searchlights, and in its centre a ruddy glow which rapidly spread into the outline of a blazing airship. Then the search lights were turned off and the Zeppelin drifted perpendicularly in the darkened sky, a gigantic pyramid of flames, red and orange, like a ruined star falling slowly to earth,” are the words reporter Michael MacDonagh noted in his journal entry dated 1st October 1916. “It was so horribly fascinating that I felt spellbound – almost suffocated with emotion, ready hysterically to laugh or cry. When at last the doomed airship vanished from sight there arose a shout the like of which I never heard in London before – a hoarse shout of mingled execration, triumph and joy; a swelling shout that appeared to be rising from all parts of the metropolis, ever increasing in force and intensity,” he added. A month earlier, right after midnight on 3rd September 1916, London experienced the ‘Night of the Zeppelins’, when as many as 16 dark cigars hovered over the British capital, each 200-metres long and each dropping bombs to the ground. They seemed to be mighty and impregnable, yet as a result of the wartime arms race, planes and anti-aircraft artillery was being perfected at an amazing pace. A few months down the line, all you needed to take down an airship was an accurately launched machine gun series with ammunition designed to puncture the aluminium shell, or a few artillery shells. When British fighter planes shot down 17 Zeppelins in 1917, the Germans backed out of the London bombings.
The bombs dropped by the airships killed 557 British subjects and caused material damage amounting to $7.5 million. Yet the construction of 17 Zeppelins cost $8.3 million, and over 300 crew members were lost. From a military and economic perspective, the balance was disastrous. Nevertheless, in the Versailles Treaty, the triumphant superpowers prohibited the production of airships in the Weimar Republic.
Fortunately, Ferdinand von Zeppelin did not live to see that day, as he had died in 1917. His successor at Luftschiffbau Zeppelin GmbH, Hugo Eckener, initiated long-term lobbying efforts in the US that lasted until 1922, when American President Warren G. Harding stated that it would be an excellent idea for Germany to pay out part of the war reparations due in brand new airships. London and Paris did not protest to this. In the meantime, engineers had developed a new generation of machines. The first LZ 120 series airship ‘Bodensee’ had the shape of a 120-metre-long ‘teardrop’, which was able to fly at a speed of 130 kilometres per hour thanks to four Maybach engines with 245 horsepower each. An improved version of the ‘Bodensee’, the LZ 127 ‘Graf Zeppelin’, was extended to 236 metres. As a result, it allowed engineers to achieve a significant increase in lift, to the point where in 1929, humanity could follow the flight of the ‘Graf Zeppelin’ around the world with fascination. At the time, the press was all over the topic of its comfortable cabins for 40 passengers, which were even equipped with separate toilets and showers with hot water, a luxurious restaurant and a lounge, indispensable for evening receptions.
But not too long after that, the factories of William E. Boeing in Seattle started to offer to airlines its innovative passenger aeroplane model, the B 247; it was a beautiful twin-engine machine able to fly at speeds of over 300 kilometres per hour. It provided a sound-proof cabin for 10 passengers with the possibility of controlling the temperature. But it didn’t outbid the offer of luxurious airships just yet; the decisive factor in this new race was... gas. German engineers replaced the flammable hydrogen with the much safer helium. They had to buy it from the Americans though, as only they had the technology available to produce helium on an industrial level. When Hitler came to power in Germany, fears were increasingly expressed across the Atlantic that a fleet of combat airships could launch an unexpected attack on American cities and ports. To the great joy of Boeing, President Franklin D. Roosevelt introduced an embargo on the export of helium to the Third Reich. So Zeppelins would once again be filled with hydrogen. The explosion of hydrogen during a landing at the airport in Lakehurst (New Jersey) on 6th May 1937 destroyed the LZ 129 ‘Hindenburg’. The catastrophe, in which 35 people were burned alive, resounded to the point that potential air travel buffs lost all trust in airships. It wasn’t such a great sacrifice for them though, as only a few months after the ‘Hindenburg’ had burned, Boeing offered them the four-engine B 307 ‘Stratoliner’, the first passenger plane with a pressurized cabin that was able to fly at an altitude of nearly 8000m and had a range of 3800 kilometres. Airlines no longer needed the giant cigars. The army used them for third-rate patrol operations at sea and as barriers attached to cables to make it harder for bombers to attack cities.
That’s how the age of the airship came to an end, but maybe not an indefinite end. According to the study concept by Hybrid Air Vehicles, the new generation vessels would be powered by electric engines supplied not only by energy from batteries, but also by energy from solar panels. That would allow the vehicle to embark on flights lasting several days continuously, not to mention neutrality for the natural environment. And that advantage can only gain importance in the very near future.
Translated from the Polish by Mark Ordon